This invention is related to an edging tool for forming a slot around a cylindrical manhole frame and in a body of concrete in which the frame is embedded.
Manhole frames typically are made of iron with a circular opening for seating a manhole cover. The manhole frame is placed in position and then wet concrete disposed around the cylindrical outer surface of the frame. The concrete adheres to the iron frame.
Due to differences in expansion and contraction rates between the iron frame and the concrete, the concrete can rise above the top edge of the manhole. If the concrete is not properly edged, this upheaving leads to spalling and cracking, reducing the life of the concrete.
Conventional practice is to form a slot about one inch deep around the top outer edge of the cylindrical manhole frame by using a tool designed to produce a straight edge. A corner of the straight edge is inserted in the concrete and moved around the manhole frame to form the slot. This is a relatively difficult process, producing a slot having an uneven depth and uneven width.
The broad purpose of the present invention is to provide an improved edging tool for forming a slot around a circular structure such as a manhole frame, in which the slot is formed between the edge of the manhole frame and the wet concrete in which the frame has been embedded.
The preferred embodiment of the invention comprises a tool body having top and bottom surfaces. The bottom surface is intended to be placed on the top surface of the wet concrete. A handle is attached to the tool for manipulating it. An elongated concave lip extends downwardly along one edge of the tool body. The lip has a circular curvature corresponding to the outer surface of the manhole frame.
The user places the lip into the soft concrete, engaged with the outer surface of the manhole frame and then lowers the tool until the bottom surface of the tool contacts the wet concrete. He then slides the tool around the manhole frame to form a slot about one inch in depth in the wet concrete.
Such a tool provides not only a more uniform slot in the cement, but is easier and quicker for the user to finish a slot. The finished slot is esthetically pleasing and professional looking.
Still further objects and; advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.